Rotary mercury vacuum-pump.



W. 'GAEDE. ROTARY MERCURY VACUUM PUMP.

APPLIOA'I'ION FILED AUG. 27, 190B.

Patented May 11, 1909.

' WGLEGANG GAEDE, OF FREIBURGQBREISGAU, GERMANY.

RQTERY MERCURY '"VAGU'UM-YUM'P.

Specification of Letters Fatent.

Patented May 11 1909.

Application filed August 27, 1908. Serial No. 50,599.

To'oll whom "it may concern:

Be it known that I, WOLFGANG GAEDE, a subject of the German Emperor, residing at Salzstrasse 13, Freiburg, Breisga-u, Germany, have invented certain new and useful Imgrovements in Rotary Mercury Vacuumi umps; and I do hereb declare the following tbe a full, clear, an exact description of the invention, such asv enable others skilled inthe art to which it appertains to make and use the same.

This invention relates to a safety device for the bucket wheels of mercur vscuum pumps, the object of the device being to pre vent damage of the bucket wheels when air is incautiously allowed to enter the pump rapidly or when the receiver suddenlybreaks.

t has been. found that the splitting of the bucket diurnalways occurs when the drum is in such 2. position that one of the highly evacuated spaces or channels in it is cut oil on all sides by mercury from the connection with 'thereceiver and the rest of thepump; If, while the drum is in this position air enters the pump quickly, the empty space in unestion is so ra idly filled with mercury, thst1t l1elatter-ctras on the wall of the drum violentlyand breelrs the wall.

The invention consists in p'rovidin the walls. whichfsre liable to receive such snocks with elasticseals, such as openings closed by elastie me'mbrenes, or spring valves. When the mercury rushes into the empty space its motion is not stopped at the moment when it fills the space but" is able to continue by virtue of the elasticity of the seal. It has been found that drums provided with such seals survive even quite sudden inrushes of air like that caused by breakage of a receiver, without any damage, even though thedrum be made ofbrittle material such as porcelain.

in the accompanying drawings, the Figures l, 2 and. 3 are diagrammatic sections through such; a drum at right angles to its axis, the drum being placed in the dangerous position.

The drum is shown of the same construc-.

tion and in the same position all the figures but the invention is inde endent of the construction of the drum 'an can be used for any part of the drum where a hollow space is cut 0% only by mercury from entering air.

Fig. 1 represents the mercury rising in the space cut off by the. mercury bath, that is to in so say in this case the channel 2, under the pressure of the entering air. The two columns are just about to meet at the point A and thereafter to produce the shock .on the wall of the drum. A v

Fig. 2 shows one form of the invention. In the outer periphery of the drum there is a number of perforations 2) '0 which are all closed by arubber band w stretched over them. V'Vhen the mercury has, filled the channel 2 it can continue to move through the opgnings raising the rubber band slightly Fig. 3 sh ows a somewhat modified form in which the perforations v o are not on the periphery. of the drum but on the end suriaces of the drum. The rubber sheet closing these holes is in this case extended over the whole surface of the drum. When a concussion occurs the rubber sheet extends slightly outward although the mercury itself doesnot escape. As soon as the mercury comes to rest it is pressed back by the elasticity of the rubber.

Fig. 4 shows another construction of the elastic seal which can be used to advantage when the openings 0 are on the end surface of the drum. The laminar spring F keeps the rubber stopper K in the perforation u,

but the pressure of the mercury from within.

the drum forces the rubber stopper outward and the valve is opened.

Having thus described my invention, I

claim:

1. In a mercury vacuum pum ,the combination/with the bucket-whee which rotates in the mercury bath, of an elastic seal in the wall of the bucket.

2. In a. mercury vacuum pump, the combination of a bucket-Wheel, a body of mercury in which the wheel rotates, and elastic seals in the wall of the bucket at places liable to fracture.

3. In a mercury vacuum ump, the combination of a bucket-wheel aving perforations in its wall, and a rubber sheet stretched over the surface of the wall and covering said perforations.

i. In a mercury vacuum pump, the combination of a bucket-wheel having a mercury channel at its outer part into which the mercury passes in two columns which move toward each other, and elastic seals comprising -a resilient member extending over the bucketwall and covering perforations eommuni- 5' In testimony, that I claim the foregoing as eating with said channel. my invention, I have signed my name in 5. In a mercury wt or pum the combi l presence of two subscribing Witnesses. nation of a bucket-w eel, an elastic seals \VOLFGANG GAEDE. 31' placed in the well of said wheel Where the i Witnesses:

are submerged when in communication wit ADOLF FUIG,

the vacuum. KARL KOPR, 

